A. Field of the Invention
The present invention relates to a new and improved reagent strip; and more particularly, to a new and improved reagent strip that can be picked up easily from a flat surface such as a table and is capable of being packaged flat in the same manner as existing, difficult to pick up, reagent strips.
B. Description of the Background Art
Measuring a person's blood sugar or glucose level has become an every day necessity for many of the nation's seven million diabetics. Because this disorder can cause dangerous anomalies in blood chemistry and is believed to be a contributor to vision loss and kidney failure, most diabetics need to test themselves periodically and adjust their glucose count accordingly, usually with insulin injections. Patients who are insulin dependant-about 10 percent to 15 percent of diabetics-are instructed by doctors to check their blood sugar levels as often as four times daily.
For years the solution for diabetics was one of several urinanalysis kits that, despite repeated improvements, provided somewhat inaccurate measurements of glucose in the blood. Examples of early urine testing for glucose are described in U.S. Pat. Nos. 2,387,244 and 3,164,534. Later, reagent strips for urine testing were developed. Although reagent strips for urine testing are still in use today this testing procedure is limited in accuracy particularly since the renal threshold for glucose spillage into the urine is different for each individual. Moreover, sugar (glucose) in urine is a sign that the glucose was too high several hours prior to the test due to the time delay in glucose reaching the urine. Readings taken from urine, therefore, are indicative of the glucose level in the blood several hours before the urine is tested.
More accurate readings have been possible by taking readings using reagent strips and blood samples from patients to determine current glucose levels. Proper dosages of insulin are also more obtainable by increasing the frequency of taking readings of glucose levels in the blood. Consequently, the advent of home blood tests has been considered by some to be the most significant advance in the care of diabetics since the discovery of insulin in 1921.
Home blood glucose testing was made available with the development of reagent strips for whole blood testing. These reagent strips include a reactant system comprising an enzyme, such as glucose oxidase, capable of catalyzing the oxidation reaction of glucose to gluconic acid and hydrogen peroxide and a substance having peroxidative activity capable of catalyzing the oxidation of the indicator. The dye or indicator in the reagent pad of a reagent strip when exposed to blood turns a visually different shade of color and the shade is an indication of the glucose level in the blood sample.
In the past the reagent strips have been flat, straight rectangular pieces of plastic with a reagent pad secured to one end of the strip. Handling of these strips has been difficult for the aged or visually impaired and often times difficult even for the normal healthy individual in that a reagent strip when lying on a flat surface such as a table top is difficult to grasp. The flat reagent strips are also difficult to pick up if the strip is on a wet surface or when the user is in a hurry to wipe excess blood off the reagent pad or to read the glucose level in an instrument after a timed reaction. In addition, reagent strips are packaged in bottles and will often stick together making separation difficult by the user or patient.